A biopsy is a procedure in which a sample of body tissue is removed and then looked at under a microscope. A core needle biopsy is the main method used to diagnose prostate cancer. It is usually done by a urologist, a surgeon who treats cancers of the genital and urinary tract, which includes the prostate gland.
Using transrectal ultrasound to “see” the prostate gland, the doctor quickly inserts a thin, hollow needle through the wall of the rectum into the prostate. When the needle is pulled out it removes a small cylinder (core) of prostate tissue. This is repeated from 8 to18 times, but most urologists will take about 12 samples.